The True Triaxial Tests Of Saturated Grit

The soil has a complex stress-strain characteristic, such as dilatancy, anisotropy, the stress path and stress history characteristics. As a very effective tool to explore the soil stress-strain relationship, true triaxial apparatus is a very important test equipment to study the soil under the three-dimensional stress state. A series of true triaxial tests were performed on the saturated coarse sand under different confining pressures, different intermediate principal stress coefficient, and under consolidated drained and undrained shear true. Then, on the basis of experimental data collected by the system,this paper analyzes and discusses it. The main content of the research work are as follows.Firstly, this paper introduced the research status of the true triaxial test apparatus, as well as development review and the test instrument itself the problems described and explains stress-strain relationship of the research methods and research progress from the angle of the soil stress-strain relationship, On this basis, this paper focuses on the dilatancy characteristics of sand, yield and strength properties, as well as consolidated drained shear and undrained stress-strain behavior under shear.Then, this paper describes the test preparations, test program and test program to achieve the true triaxial test test steps.While, on the basis of the test results analysis and discussion, this paper deduces and obtaines stress-strain behavior of the sand under different confining pressures, different intermediate principal stress coefficient, drained and undrained and analyze the cause of this different reasons. Results based on the angle of major principal stress direction and deposition in a different direction of the stress-induced anisotropy and the original anisotropy on the deformation and strength of sand.Finally, based on the Lade-Duncan elastic-plastic model theory, this paper analyzes and discusses the relationship between the yield function and plastic potential under different intermediate principal stress; the relationship between the plastic work and the potential yield and plastic potential; the relationship between plastic potential and yield potential under different confining pressures. And further to combine Matsuokaka-Nakai failure criterion, this paper analyzes the strength and deformation characteristics of saturated sand under principal stress coefficient, at the end, this paper predicts the failure strength of the soil by using of more extensive application of these two failure criteria.